1. Field of the Invention
This invention relates to disk drive suspensions, and more particularly to disk drive suspensions comprising a load beam actuated to different disk tracks by a microactuator. In the invention, the microactuator typically comprises a piezoelectric crystal that is electrodynamic to expand or contract responsive to an input of a voltage. This phenomenon enables micro adjustment of the position of the load beam rigid portion carrying the slider relative to the disk for reading or writing data. In a specific aspect, the invention relates to improvements in the coupling of the microactuator to the load beam for the microactuation movement.
2. Related Art
Microactuation of load beams with piezoelectric crystals has relied on adhesive bonding. In many cases there is insufficient real estate on the opposing load beam portion surfaces and the piezoelectric crystal surfaces to deposit the quantity of adhesive needed to bond the parts against the forces encountered in use of the suspension.
It is an object of the invention to provide an improved assembly of a load beam and microactuator. It is a further object to provide a combination load beam and microactuator positively coupled together by interfitting elements of the load beam and microactuator. It is another object to provide a method of assembling a load beam with a microactuator piezoelectric crystal by increasing the opposing surfaces of the parts and bonding the parts with adhesive. It is a highly particular object to provide interfitting receiving and inserting structures on the microactuator and load beam such as notches and holes that positively couple corresponding structure such as tabs, rails, pins, and the like.
These and other objects of the invention to become apparent hereinafter are realized in a disk drive suspension comprising a load beam having a base portion, a spring portion, and a beam portion adapted to carry a slider in operating proximity to a disk, and a dimensionally variable electrodynamic microactuator, the load beam and microactuator defining cooperating interfitting structures, the microactuator acting through the interfitting structures being arranged to selectively displace the beam portion relative to the base portion.
In this and like embodiments, typically, the load beam and microactuator are bonded together at the interfitting structures, the microactuator comprises a piezoelectric crystal, the crystal extending in a plane and defining an interfitting structure comprising at least receiving element, the load beam extending in a plane generally parallel to the crystal plane and defining an interfitting structure comprising at least insertion element, the receiving and insertion elements cooperating in interfitting relation to interlock the crystal and the load beam in shear in their planes, the microactuator comprises a piezoelectric crystal, and the suspension includes right and left hand microactuators acting from the base portion on the beam portion in displacing relation.
In another embodiment, the invention provides a disk drive suspension comprising a load beam having a base portion, a spring portion, and a beam portion adapted to carry a slider in operating proximity to a disk, and a dimensionally variable electrodynamic microactuator, interfitting male and female structures defined by the load beam and microactuator, the microactuator acting through the interfitting male and female structures being arranged to selectively displace the beam portion relative to the base portion.
In this and like embodiments, typically, the microactuator comprises a piezoelectric crystal, the piezoelectric crystal having notches inward from an edge at longitudinally spaced proximate and distal locations along the edge to define the female structure, the load beam base portion defining a first male structure interfitting the proximately located notch, the load beam rigid portion defining a second male structure interfitting the distally located notch, the microactuator comprises a piezoelectric crystal, the piezoelectric crystal having notches inward from its left and right edges at longitudinally spaced, opposed proximate and distal locations to define the female structure, the load beam base portion defining opposed, laterally spaced first male structures interfitting the proximately located notches, the load beam rigid portion defining opposed, laterally spaced second male structures interfitting the distally located notches, the notches are generally rectangular and transverse to the long axis of the piezoelectric crystal, the first and second male structures being generally congruent with the notches, the first and second male structures comprise bent up tabs from on the respective load beam portions, the first and second male structures extend transversely of their respective load beam portions and in parallel with each other, the first and second male structures extending transversely an extent greater than the transverse extent of the notches so that the male structures project laterally from the piezoelectric crystal notches in their interfitted condition.
In this and like embodiments, further, the microactuator comprises a piezoelectric crystal, the piezoelectric crystal having apertures inward from an edge at longitudinally spaced proximate and distal locations along the length of the crystal to define the female structure, the load beam base portion defining a first male structure interfitting the proximately located aperture, the load beam rigid portion defining a second male structure interfitting the distally located aperture, the microactuator comprises a piezoelectric crystal, the piezoelectric crystal having apertures inward from its left and right edges at longitudinally spaced, opposed proximate and distal locations to define the female structure, the load beam base portion defining opposed, laterally spaced first male structures interfitting the proximately located apertures, the load beam rigid portion defining opposed, laterally spaced second male structures interfitting the distally located apertures, the apertures are generally rectangular and transverse to the long axis of the piezoelectric crystal, the first and second male structures being generally congruent with the apertures, the first and second male structures comprise bent up tabs from on the respective load beam portions, the apertures are tapered down in the direction of insertion of the male structures.
In yet a further embodiment the microactuator comprises a piezoelectric crystal, the piezoelectric crystal having generally rounded holes between its edges at longitudinally spaced proximate and distal locations to define the female structure, the load beam base portion defining a first male structure interfitting the proximately located hole, the load beam rigid portion defining a second male structure interfitting the distally located hole.
Yet further, the microactuator comprises a piezoelectric crystal, the piezoelectric crystal having generally rounded first and second holes on its longitudinal axis at longitudinally spaced, opposed proximate and distal locations to define the female structure, the load beam base portion defining a first male structure interfitting the proximately located first hole, the load beam rigid portion defining a second male structure longitudinally spaced from the first male structure and interfitting the distally located hole, the holes are circular, the first and second male structures each having a generally conical base generally congruent with its the hole in hole engaging relation to couple the piezoelectric crystal to the load beam portion, the first and second male structures comprise projections from the respective load beam portions, the first and second male structures extend in parallel with each other, the first and second male structures extending normal to the plane of their respective load beam portions an axial extent less than the axial extent of the holes in their interfitted condition, the first and second male structures projections are formed by etching away load beam portion areas surrounding the projections, or the first and second male structure projections are formed by deflecting the load beam portions about a forming tool.
In its method aspects the invention provides a method of bonding a load beam and a piezoelectric crystal having opposing surfaces, including reshaping the crystal surface to increase its area opposite the load beam, reshaping the load beam opposing surface to increase its area, applying adhesive to at least one of the opposing surfaces, and bonding the opposing surfaces together with the adhesive.